Hey, I find everything interesting. Seriously I like looking at fringe research and theory even. I think what your running into here is the fact that RS research seems to be found most prevalently in the realm of cereal grains and other CW "get your fibers" sort of talk. Not gonna go over well with the Primal crowd you know.

I think people are a bit more forgiving of the tator hypothesis posed by PHD because its based on relatively small amounts of starch for glucose that is based on an evolutinary model and fits a Primal plus intense exercise template.

Well for one...I couldn't find the citation. I found the statement that you "have seen", but not the citation. I coulda missed it though if you wanna repost that. The experiment could be interesting to read.

Other types of fiber haven't been shown to improve insulin sensitivity like this (no exercise, no weight loss, immediate results). The Diabetes Prevention Program was able to achieve 53% improved insulin sensitivity with intensive exercise, counseling and weight loss.

I still think it's pretty essential to have a healthy and functioning gut.

.....I still think it's pretty essential to have a healthy and functioning gut.

Me to, with the caveat that it is functioning well for the diet you are actually eating.

I appreciate the links...although the second one wasn't working. I think I'll just let this go and say its clearly an interesting phenomenon in the research arena particularly because they have not identified the mechanism.

It seems to me raw potato is about the same as a green banana. Both are fairly edible. The greener a banana the harder it is to eat. Plantains probably also fit in here, but they are nearly impossible to eat raw--make your mouth pucker!

So, RS Queen, in your estimation then 5g is enough to make a noticeable difference for you? Have you tried bigger (30g) doses?

I put bananas in smoothies with other fruit, so I don't taste it at all. I've tried plaintains, but they're tougher to eat so I didn't buy them again. I've tried two tablespoons (10 g) doses in smoothies with other RS foods later the same day, so I probably got in the range of 20 grams in that day. I haven't seen anything more than I already get with 5 g, but I'm not trying to lose weight or trying to reverse insulin resistance. I'm overall pretty healthy and just want to keep everything healthy and running smoothly. The studies that fed people 30 g/day found that people sometimes got gas.

It seems to me that it is fairly agreed upon that a small amount of SCFA may be beneficial for colon health.

One question that was posed, I think by Paleobird, was whether getting glucose to the large intestine via whatever means (RS, beans, etc.), to be fermented by bacteria to create SCFA is the only way of getting it, as opposed to ingesting it through, say, butter.

They measure directly the concentration of the 3 SCFA acetate, propionate, and butyrate directly in the portal vein which absorbs them from the gastrointestinal tract, in the liver, and in the spleen. They do this to see how much is released into the bloodstream via digestion, how much is taken up by the liver, and how much is available to the rest of the body (spleen measurement). The study was done to assess the safety of adminstering SCFA orally for therapeutic purposes.

The present study showed that the gut is the main SCFAs-releasing organ and the liver is subsequently able to take up virtually all butyrate and propionate in patients with normal liver function.

After release into the portal vein, propionate and butyrate are metabolized by the liver and used for gluconeogenesis, whereas acetate is a substrate for lipogenesis, cholesterol synthesis and is taken up by adipose and muscle tissue.

the liver appears to prohibit escape of gut-derived butyrate and propionate into the systemic circulation

So actually you can't get SCFA delivered to the colon via blood circulation because the liver takes it all, metabolizes and prevents its return to the blood stream. This is a natural and important process because SCFA are actually toxic to the body.

On the one hand, Otzi is right in the sense that you must ingest some form of indigestible polysaccharide (whether RS or some other type) in order to have SCFA available to colon cells. On the other hand, PK is right because whether you eat beans or you eat raw potatoes, it's gonna get fermented as simple monosaccharides in the colon.

I think the problem is that most of these studies are conducted on average SAD eating people whose diet and colon, I believe it's safe to say, are not particularly healthy. So it's possible that encouraging resistant starch consumption and SCFA production may benefit the colon or benefit the insulin response. However, I do not necessarily see the jump in logic where we say that for a healthy primal eating individual who doesn't have insulin resistance, who's got plenty of good fat intake, who is adapted to fat-burning instead of sugar burning, who is avoiding nasty vegetable oils, who has a healthy gut with regular movements, that eating additional resistant starch will further reduce the risk of colon cancer, improve colon health, or improve insulin sensitivity. Think of it as the law of diminishing returns.

On a more personal note, and for my N=1 thing, I do need some carbs. Around 100g/day in bananas, yogurt, fruit, and the occasional potato keeps me happy and non homocidal. But I can't eat lots of potatoes, even 2 cooled ones at the same time because I can feel my insulin response spiking and it makes me feel not good. I've had acne flare ups from over eating those "safe" starches. I also didn't appreciate the excessive gut fermentation that went on.

Another N=1. My mom got colon cancer and she was the slim healthy looking poster child of CW. Daily fiber in the form of whole wheat, soaked overnight legumes, vegetables, fruits, lean meats, the latest "healthy oil" fad, lots of white rice with stews which is a staple where I am, potatoes, avoided refined sugars, and an obsession with low low low fat. None of that resistant starch saved her colon.

For me the end sum is eat primal, eat some carbs, eat proteins and eat fat. If it's causing your gut or body distress keep it off the menu. If potatoes and white rice work for you as a food source, great, but they aren't some miracle food that will save your colon if your body isn't healthy. And if your body is healthy, then your colon cells are getting what the rest of your body is and they don't saving anyway.

...For me the end sum is eat primal, eat some carbs, eat proteins and eat fat. If it's causing your gut or body distress keep it off the menu. If potatoes and white rice work for you as a food source, great, but they aren't some miracle food that will save your colon if your body isn't healthy. And if your body is healthy, then your colon cells are getting what the rest of your body is and they don't saving anyway.

I agree as well. Nobody knows what constitutes health or what a healthy colon looks like. I have great respect for someone who figures out what works for them and sticks with it. I also have great respect for keeping an open mind and considering new data.

Point - There have been two major international clinical studies to see if RS prevents colon cancer. One was in people with familial polyopsis and the other was in people genetically predisposed to colon cancer (Lynch syndrome). Neither one showed reduced risk of colon cancer with RS. There's still a lot of debate about whether the doses in these studies were too low, but the fact is - they fed hundreds of people RS from raw potatoes, retrograded high amylose cornstarch or granular high amylose cornstarh and it didn't stop the progression of the cancer. More cancer prevention trials are still underway so researchers are still tryinig to figure it out.

Question - if eating carbs makes you feel lousy, how can you not be insulin resistant?

This was presented at a scientific meeting in June - It's even less appealing than raw potatoes or green bananas. CSIRO in Australia has worked with RS for years. They found people that had developed colitis and reversed it with RS suppositories. Pretty good evidence that RS helps colon health. I guess it'll eventually get published, but here's the basic info.
Roediger W, Le Leu R, Jones T. Clinical practice/guidelines (nutrition) - PMO-047 Diversion colitis treatment with rapidly fermentable fibre-suppositories. Gut 2012;61:A93 doi:10.1136/gutjnl-2012-302514b.47. Digestive Disorders Federation Meeting 17–20 June 2012 Liverpool, England.

I agree as well. Nobody knows what constitutes health or what a healthy colon looks like. I have great respect for someone who figures out what works for them and sticks with it. I also have great respect for keeping an open mind and considering new data.

Point - There have been two major international clinical studies to see if RS prevents colon cancer. One was in people with familial polyopsis and the other was in people genetically predisposed to colon cancer (Lynch syndrome). Neither one showed reduced risk of colon cancer with RS. There's still a lot of debate about whether the doses in these studies were too low, but the fact is - they fed hundreds of people RS from raw potatoes, retrograded high amylose cornstarch or granular high amylose cornstarh and it didn't stop the progression of the cancer. More cancer prevention trials are still underway so researchers are still tryinig to figure it out.

Question - if eating carbs makes you feel lousy, how can you not be insulin resistant?

This was presented at a scientific meeting in June - It's even less appealing than raw potatoes or green bananas. CSIRO in Australia has worked with RS for years. They found people that had developed colitis and reversed it with RS suppositories. Pretty good evidence that RS helps colon health. I guess it'll eventually get published, but here's the basic info.
Roediger W, Le Leu R, Jones T. Clinical practice/guidelines (nutrition) - PMO-047 Diversion colitis treatment with rapidly fermentable fibre-suppositories. Gut 2012;61:A93 doi:10.1136/gutjnl-2012-302514b.47. Digestive Disorders Federation Meeting 17–20 June 2012 Liverpool, England.

I am so glad you chimed in on here. Excellent papers, too. You know people think you are really me, right? Whoever you are, thanks!